Leather-stretching mechanism



(NoModel.) 2 sheetsfshet 1.

. G. & E, A. NOBLE.

LEATHER vSTEETGEIIlfTGr MEGEANISM..

Patented Feb. 1, 1898;.

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2 Sheets-Sheet 2.

(No Model.)

G.H. a F. A. NOBLE. LEATHER STRETCHING MECHAYISM.

Patented FebIv l, 1898..

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Erzi? STATES PATENT GEORGE H. NOBLE AND FRANK A. NOBLE, OF WORCESTER, MASSACHUSETTS.

LEATHER-STRETCHING IVI EC HANI'SIVI.

SPECIFICATION forming part of Letters Patent No. 598,20*?, dated February 1, 1898.

Application filed August 2, 1897. Serial No. 646,805. (No model.) i

To all whom t may concern,.-

Beit known that we, GEORGE H. NOBLE and FRANK A. NOBLE, citizens of the United States, residing at l/Vorcester, in the county of .Worcester and State of Massachusetts, have invented a new and useful Leather-Stretching Mechanism, of which the following, together with the accompanying drawings, is a specification suciently full, clear, and eX- act to enable persons skilled in the art to which this invention appertains to make and use the saine.

Our present invention relates to mechanism more especially designed and intended for stretching leather preparatory toV its being worked into belting for machinery and in which strips of leather cut approximately the width for the required belts can be put under severe strain while wet and then allowed to dry in their stretched condition.

The objects of our invention are to afford a more practical and eflicient mechanism for the purpose named and to provide an improved jaw or means for holding the end of the leather strip with a secure grip under varying strains and which can be quickly and conveniently manipulated for entering and releasing the leather into and from the same.

Another object is to provide a leatherstretching machine having stretcher devices provided with means for adjustment to accommodate different widths of belting or for operation with removable stretcher-racks of various sizes or widths.

Another object is to provide a leatherstretching machine with front and rear sets of jaw-supporting appliances and holdingjaws adapted for stretching two pieces of leather simultaneously; and also to afford fa-l cilities for equalizing the draft or overcoming variations in the elongation or increase in length of the two pieces operated upon.

Another object is to provide in a stretching-machine a yielding stretcher-head with means for regulating or limiting the amount of strain applied to the leather, and also to affordin connection therewith means for automatically controlling the action of the machine when the strain has reached the desired limit of tension.

These objects we attain by the mechanism illustrated, the particular subject-matter claimed being hereinafter definitely specified.

In the drawings, Figure l is a side view of a leather-stretching machine embodying our invention. Fig. 2 is a vertical section of the front portion of such machine. Fig. 2a shows the jaw-support as made non removable. Fig. 3 is a transverse section of our improved clamp or holding-jaws for leather-stretching machines. Fig. 4E is a front view of the machine with the racks out. Fig. 5 is a front View of the removable rack with leather therein. Fig. 6 is a side view of the same, and Fig. 7 is a plan section showing the detail of the holding-jaws.

Referring to the several parts and combinations in detail, A denotes the main frame, of. suitable form and construction to properly support the working mechanism.

.B and C indicate,respectively, the stretcherhead and jack-slide mounted in corresponding alinement in suitable guideways or grooves a on the front uprightsof the frame A, so as to have movementt'oward and from each other. The jack-slide O is provided with gear-racks 3 at its sides, that engage with Vpinions 4, mounted upon a rotatable shaft G, arranged in bearings fixed on the frame adjacent to the guideway-standards. This jack-shaft G has a ratchet-Wheel Gr secured thereon, and for imparting motion thereto we employ a reciprocating rod H, carryinga hinged pawl h, that engages the ratchets. Said rod is best operated by a crank or eccentric h2 and suitable driving mechanism, as the gears, shafts, and drive-pulleys shown at K K', or by other means. The paWl-hinge is supported by an arm` that swings on the axis or hub, as indicated by dotted lines, Fig. l. An adjustable swinging guard J is arranged for intervention beneath the pawl h to throw it out of action, as more fully hereinafter explained. The .wheel Gr.' is best furnished with a handcrank g, and a stop-pawl is arranged adjacent thereto for. retaining the jack mechanism at position when the pawl h is thrown off.

The head B and jack-slide O are provided with carrier-arms, jaw-supports, or brackets D and D', that project therefrom inthe present instance at both the' front and rear sides. Said arms have thereon detents or bosses 5 for centering and supporting the leatherholding jaws F or stretcherracks, as hereinn after explained. j

` E indicates a removable rack or stretching- IOO form comprising the upper and lower pairs of gripping-jaws F, and adapted to be adjusted upon the carrier-arms D D for receiving the work and to be removed therefrom to facilitate the drying of the stock before its release from the stretched condition. These racks E are composed of side rods or bars e, having the end blocks l, that support the grippingjaws F, arranged at the upper and lower ends of the side rods, forming a rectangular open structure adapted for holding the piece of leather L, as indicated in Figs. 5 and 6.

Our improved jaws consist of a pair of hollow semicylindrical or shell-shaped bars longitudinally straight and disposed parallel with each other and eccentrically journaled at both ends in the end blocks I, the two jawbars being connected or intermeshed with each other at one end (or both ends) by toothed gearing f, so that the two bars will have opposite rolling action in positive unison with each other, bringing the curved outer surfaces nearer together or farther apart on parallel lines at opposite sides of the central space m, accordingly as the jaw-bars are rocked in one direction or the other for gripping or releasing the leather across the entire width of the strip L. A transverse hole 7 is formed in the j aw-bar for the insertion therein of a hand rod or lever 8, by means of which the jaws can be closed or opened. The exterior surface of one of the jaw-bars in each pair is preferably fluted for insuring a more secure hold upon the leather. Vhen gripped upon the leather, the holding power of the jaws increases as the pulling strain on the leather increases. The end blocks I may be connected togetheracross the rack by tie-rods t', as indicated in Fig. 7, or in other suitable manner. The end blocks are fitted with recesses or depressions d to match the detents or bosses 5 on the carrier-arms D D, so that they can be readily adj usted upon and securely supported in connection with said arms, as illustrated in Fig. 2.

In the preferred construction of the racks one set of jaws has its end blocks I rigidly secured to the side rods, while the other set of jaws has its end blocks combined with said side rods in a manner to slide thereon, said rods being provided with a row of outwardlydirected Vratchets 9 and the end blocks provided with pivoted spring-pressed pawls 10, that engage with said ratchets and normally prevent inward or contractile movement of the jaw-block, While allowing free outward or extension movement thereof. The pawls are provided with projecting tails adapted for pressure by the thumb for disengaging the point of the pawl from the ratchets when it is desired to adjust the jaw inward on the rods. (See Figs. 3, 5, and 6.)

The carrier-arms D and D may be either fixed or movable in the head and jack-slide frames. In the present instance said carrierarms are shown as arranged laterally adj ustable, so as to accommodate racks E of various widths, thus adapting the machine for different widths of belting. Shafts s and s' Aare fitted through the parts D and D' with right and left screw-threads for effecting an outward and inward lateral adjustment of said parts by rotation of said shafts. (See Fig. 4.)

The upper carrier-arms D are best arranged to have tilting action on a central axis fn, so as to be self-adjusting to accommodate any variation in the stretch of the two pieces of leather at front and rear of the head under a given tension or strain.

rIhe head B is preferably suspended by chains or links Z) b .from a rock-shaft M, arranged across the top of the frame, suitable sprockets or equivalent devices being fixed on said shaft for connecting the chain-links thereto. On the end of said shaft there is a head-plate N; carrying a pawl 12, that engages a ratchet-wheel 13, fixed to the shaft, the pawl holding the ratchet and shaft in opposition to the downward pnll of the head B. One end of the rocking head N is joined by a link 14 to a swinging arm or lever P, fulcrumed on the frame at 15, and hung upon said arm is an adjustable poise or weight P. The other end of said rocking head N is connected by a rod J with the swinging guard J of the jack-operating ratchet G.

The operation is as follows: The pawl h is swung up from the wheel G, and by means of the hand-crank g the j ack-shaft Gis turned backward, so as to elevate the slide C. The pawl c is then turned in to temporarily hold the parts in place while adjusting the work. The racks E being placed on the carriers D D, the jaws F are opened by means of the lever 8, the end of the leatherLplaced between, and the jaws closed thereon. When the two strips at front and rear of the stretching-j ack have been placed in position, pawl @cis thrown out and pawl h thrown into engagement and the driving mechanism started by shifting the belt to the tight pulley at K. The reciprocation of the rod H and pawl h operates the jack-gearing and depresses the slide C, which by its carrier-arms D forces downward the lower sets of jaws and stretches the leather from the Lipper jaws. When the strain upon the head B, which carries the upper jaws, becomes so great that acting through the chains b, shaft M, and arm P it overcomes the resistance of the poise P', the arm swings upward, allowing the shaft M and its plate N to rock forward as the head B is drawn down.4

given to the leather is retained by the ratchet 9 and pawl device 10, that connect the lower jaw-blocks with the side bars of the racks. Any variation in the stretch of the outer and inner strip is relieved by the tilting of the IOO IIO

upper carrier-arms D on their aXis n, as indicated in Fig. 3. The jack-shaft is neXt turned backward, raising the slide and thereby releasing the racks E, which, with the leather still held stretched therein, are taken from the machine and hung up or placed away to allow the leather to dry in stretched condition, and other racks are introduced into the machine and the operation repeated. When the leather is dry or at any time as desired, it can be released from the rack-jaws or clamp F by turning .back said jaws with the Vhand-lever 8.

The limit of yielding tension for the head B can be varied by adjusting the poise P along its arm, or, if desired, the head may be fixed in its support by a positive stop, as a pin or dog arranged in suitable manner to prevent its movement in the main frame.

In some instances, as for stretching leather for very wide belting or where an eXtra large and powerful machine is required, it may be desired to have the machine single or'without removable racks E. In such cases the jaws F can be journaled directly in the carriers, asindicated in Fig. Qa-that is, in cheeks that form a rigid and permanent part of the stretcher-head B or jack-slide C.

Our improved leather-holding jaws F herein described can be applied or used in stretching-machines with operating mechanism of other form than that herein shown, and we desire to include such jaws when so ,used as within the scope of our invention.

Ve claim as of our invention and desire to secure by Letters Patent l. In a leather-stretching machine, the removable stretcher form or rack constructed as described, and composed of the parallel side rods and automatic grip holding-jaws disposed at the respective ends thereof; said jaws adapted lfor holding the leather in straight condition and stretched in a central plane coincident with the axes of said side,

rods; the end blocks having central seats for suspension on the machine, the blocks orbearings of one pair of jaws rigidly Xed to the rods, and the bearings of the other pair of jawsiitted to slide on said rods and provided each with a spring-pressed pawl pivoted in said bearing, its point adapted for engaging the outwardly-directed ratchets formed on the side rod, and having a thumb-tail for the release of the pawl; all substantially as and for the purposes set forth. y 2. In a leather stretching machine, the holding-jaws F consisting of a pair of opposite, longitudinally parallel, semicylindrical or transversely curved bars, eccentrically journaled at both ends in non-yielding bear- .ings common to the pair, and said bars connected or intermeshed by toothed gears adjacent to their ends, substantially as shown and for the purpose set forth.

3. In a leather-stretching machine, the combination with the stretcher head and jack mechanism, of a front set of holding-jaws and a rear set of holding-jaws, and means bination, with a stretcher head and jack slide mounted to work in guides on the supportingframe, and provided with carriers or lugs adapted for seating jaws thereon; of the removable clamps or holding-jaws comprising the pairs of parallel transversely-curved bars eccentrically journaled in bearing blocks, said bearing-blocks fitted with recesses or surfaces adapted to match said seat-lugs or carrier-surfaces on the head or jack-slide, and to receive working support for said jaws thereon during the stretching action, substantially as set forth.

5. ,The stretcher-head provided with tilting carrier-arms, in combination with the jackslide, and lleather-holding jaws at front and rear of said head and slide, for the purpose set forth.

6. In combination vwith the stretcher-head, the j ack-slide, and detachable clamps or holding-jaws; the jaw-supports or carrier-arms laterally adjustable within said head and jack-slide, and adapted for sustaining said detachable jaws of various widths, and the right and left threaded screw-shaft or means foreftecting adjustment of said carrier-arms, substantially as set forth.

7. In a leather-stretching machine, the combination with the stretching-jack and leatherholding jaws, of the movable jaw-supporting head, its suspending-links, the rocker-shaft supporting said head, the ratchet-connected plate on said shaft, the pivoted balance-arm connected therewith, and the `poise or weight .adjustable on said varm, for the purpose set forth.

8. ln a leather-stretching machine, the combination, of the stretcher-jack C and jackoperating shaft provided with a ratchet-wheel G', the actuating-pawl h and the swinging guard piece J,. the stretcher -head B, the rocker-shaft M supporting said head, the shaft head-plate N, its connecting-ratchet 13 and pawl l2, the 4balance-arm P linked to said plate, and the rod J connecting said plate with the swinging guard that controls the jack-actuating mechanism, and means for retaining the ends of the leather strip in connection with the stretcher head and jack, all substantially as and for the purpose set forth. i

Vitness our hands this 29th day of July,

GEORGE ll. NOBLE. FRANK A. NOBLE.

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